Mill liner handling machine



United States Patent Karl E. Nenmeier Stillwater, Minnesota Sept. 23,1968 Programmed 8: Remote Systems St. Paul, Minnesota a corporation ofMinnesota MILL LINER HANDLING MACHINE 14 Claims, 13 Drawing Figs.

U.S. Cl

Int. Cl

Field of Search 182,183,134,iRCM,147T;212/17,55,59,l25, 128,129;l04/93,95,l73;105/30,150,152,154,

[56] References Cited UNITED STATES PATENTS 2,744,472 5/1956 Symons105/154 3,214,033 10/1965 Nilsson.... 212/55 3,235,097 2/1966 Ohman.....212/55 3,255,893 6/1966 Hainer 214/1 FOREIGN PATENTS 203,492 4/1966Sweden 214/1 Primary Examiner-'Gerald M. F orlenza AssistantExaminer-George F. Abraham Attorney-Dugger, Peterson, Johnson & WestmanABSTRACT: A machine for handling the heavy linings of mills, inparticular taconitegrinding mills that have to be periodically changedafter use. The machine can be utilized for a plurality of mills byremovably mounting the machine on rails positioned adjacent the mill tobe serviced. The machine has its base positioned outside of the mill,and has arms that will reach into all portions of the mill to remove andreplace the liner sections. The arms can be folded back to make acompact unit for storage.

COMIROAUFR Patent ed Nov. 17, 1970 3,540,603

Sheet 1 of6 M Q MWYM lrroruers Sheet I Patented Nov. 17, 1970 llllllmmlN lm Patented Nov. 17, 1970 I 3,540,603

HHHII KAeL E. A/EU/Vf/A'R Patented Nov. 17, 1970 Sheet m MIN MI W- K419iE MAY/MEYER 4 rromvsr:

Patented Nov. 17, 1970 3,540,603

Sheet 5 of6 Irwin/5r:

Patented Nov. 17, 1970 Sheet FIE. 1.2

. 1 MILL LINER HANDLING MACHINE BACKGROUND OF THE INVENTION v I. Fieldof the Invention The present invention relates to handling booms or armsfor handling the linings of large mills.

2. Description of the Prior Art Various types of booms have beenadvanced for doing many different jobs. However, in the use in taconiteplants, in particular, there has been a need for an extremely heavy-dutymachine which can handle heavy lining members of the mill, which arebolted into place on the mill frame, and which can remove these linermembers, and then replace them with new liner members. In doing so, theboom has to work around corners and be able to reach the remote cornersof the mill.

SUMMARY OF THE INVENTION The present invention relates to a jointed boomhaving a base removably mounted on rails. The base can be moved alongthe rails. The arm or boom is jointed so that it can go into remotecorners of a mill, for example, and can be used for removing liningmembers and replacing them with new liners. The boom is removable fromthe rails for transport to other locations for relining other mills. Theboom inner section is offset to permit the boom to be folded back uponitself for storage. The boom has a section that is rotatable aboutvertical axis, an outer section which is longitudinally extendable andalso has portions that are rotatable about a substantially horizontalsection. The mill includes a gripping device which is rugged duty, andwill rotate fully around a vertical axis, as well as a limited amountabout a horizontal axis to facilitate the grasping of the mill linersthrough the use of an adaptor for this purpose.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top plan view of a millliner handling'machine made according to the present invention;

FIG. 2 is a side elevational view of the device of FIG. 1 taken as online 2-2 in FIG. 1;

FIG. 3 is a fragmentary enlarged side elevational view of a supportcarriage for the mill liner handling machine with parts in section andparts broken away;

FIG. 4 is a view taken as on line 4-4 in FIG. 3;

FIG. 5 is a fragmentary enlarged side elevational view of a grippingmember used with the device of FIG. 1 with parts in section and partsbroken away;

FIG. 6 is a side elevational view of the device of FIG. 5;

FIG. 7 is a vertical sectional'view of the bracket for mounting the baseportion of the boom viewed in opposite directions from FIG. 2;

FIG. 8 is a view showing the mounting of a gripping assembly with partsin section and parts broken away;

FIG. 9 is a sectional view taken as on line 9-9 in FIG. 2;

FIGS. 10 and 11 are top and side views of an alternate device for movingthe base assembly; and

FIGS. 12 and 13 are top and side views of a handler device to replacethe grip member.

DESCRIPTION OF THE PREFERRED EMBODIMENT I members to suspend the beamsthe required distance from the floor or ceiling and adjacent to the mill14. The rails 13,13 are comprised as "1 beams having a center web 15 andtop and bottom flanges 16. The I beam section is shown partially in FIG.4. A support carriage assembly 17 is mounted onto these beams and ispositioned for movement back and forth in direction along the I" beams.The carriage assembly comprises a pair of main crossmembers 20,20mounted onto and fixedly attached to a pair of spaced apart supportmembers 21,21 which hold the crossmembers 20,20 in an assembly. Thesupport members 21 extend parallel to and are below the rails 13,13. v

The crossmembers 20,20 are supported on the rails 13,13 with rollerhangers 22. There is one of the roller hangers at each end of thecrossmembers 20. The hangers in this instance are made in a uniquemanner so that they can be released from the rails when the assembly isto be moved to a different location, or during storage when the machineis not being used.

A hoisting framework 23 is also supported by the members 21, 21 and hasa device or support bar 24 on which a hook or other hoisting device canbe placed for raising and lowering the carriage and mill handler machineassembly into place or removing it from the rails 13.

A framework 25 is utilized for mounting an electric motor 26 andhydraulic reservoir 27 and pump 28 (schematically shown) which are usedfor powering the components of the mill liner handling machine. Theelectric motor 26 is powered through a conventional source of power. Themotor moves right along with the machine.

Once installed, the assembly is moved back and forth along the rails 13through the use of a hydraulic cylinder 30 which can be extended orretracted. The base end of the cylinder 30 is attached to a bracket 31that is mounted into a suitable support on the building, or on the rails13, and the rod end, which extends and retracts is attached with thebrackets 32 to one of the crossmembers 20, and upon extension orretraction of the cylinder 30 the entire carriage will be moved back andforth along the rails.

A main support tube 35 is fixedly attached with a base member 36 to thesupport members 21 at one side of the carriage, and extends downwardlytherefrom. A support bracket assembly 35A is fixed to the tube 35. Ashaft 37 (see FIG. 7) is rotatably mounted on suitable hearings in thesupport bracket assembly. The shaft 37 supports a boom-mounting bracket38. A hydraulic motor 39 drives through a gear box 39A that has anoutput shaft drivably mounting a small sprocket 398. A large sprocket35B is fixed to the bracket assembly 35A. When the motor 39 drives thesmall sprocket 39B, a chain 39C between the sprockets causes the smallsprocket, the gear box, and the bracket 38 to orbit, or in other words,to rotate about the bracket 35A and thus about the axis of tube 35. Theshaft 37 rotates on bearings 37A with respect to the bracket 35A.

A base boom section 40 is pivotally mounted about an axis 41 to thebracket 38, and the base boom section will move back and forth aboutthis pivot in direction as indicated by the double arrow 42 apreselected number of degrees (see FIG. 7

2). A pair of support arms 43 extend downwardly from the main part ofthe bracket 38 and a hydraulic cylinder 44 is mounted as at 45 to andbetween the arms 43. The rod end of the cylinder 44 is attached as'at 46to brackets 47 welded directly to the base boom section 40. Brackets 47are on the underside of the boom, as is the cylinder 44, and uponextension and retraction the boom can be raised or lowered. As shown,the boom will not move downwardly below a substantially horizontalposition, and in this manner, which is the usual working position, thecylinder 44 offers its maximum support for the inner boom section, whichhas to carry a tremendous amount of load because of the heavy mill linersections.

The outer end of the main or inner boom section 40 has a bifurcatedoffset housing 50 at the outer end thereof. The bifurcated sectionincludes an upper arm 51 and a lower arm 52. These sections are offsetso that they extend laterally from the axis of the inner boom section. Amounting housing 53 is mounted between the arms 51 and 52 on a shaft 54mounted in suitable bearings in the arms 51 and 52. A hydraulic motor 55is mounted on arm 51 and has an output or drive shaft directly coupledto the shaft 54 to rotate it about its upright axis indicated at 56. Themounting housing 53 can thus be rotated under power. The housing 53 hastwo spaced apart side plates 60,60, and an outer boom assembly 61 ispivotally mounted about an axis 62 on a suitable pin. The movement ofthe outer assembly 61 about pivot axis 62 is controlled through the useof a hydraulic cylinder-piston assembly 63 which is mounted at its baseend as at 64 between the plates 60,60. The rod end of the cylinder ismounted as at 65 to a bracket 66 attached to the outer boom assembly 61.

The outer boom assembly 61 has two sections and is longitudinallyextendable and retractable. A boom slide member 70 is slidably mountedin the base section 71 of the outer boom assembly on suitable rollers.As shown in FIG. 9, the slide member and base section 71 are rectangularin cross section. The slide member 70 has guide ribs 70A and 70B onthetop and bottom thereof, and rollers 77 are rotatably mounted on thebase section and guide against the member 70 on opposite sides of theseribs to keep the slide member from twisting about its longitudinal axis.This gives great stability to the extending boom. The hydraulic cylinder72 is mounted as at 73 to brackets 74 attached to the top of the basesection 71 of the outerboom assembly 61 and the rod end of the cylinderis attached as at 75 to a support bracket 76 fixedly attached to theouter end of the slide member 70.

Support bracket 76 is used for mounting a gripping assembly illustratedgenerally at 80. The gripping assembly includes a yoke 81 which isU-shaped, and which is fixedly attached to a shaft 82 that is rotatablymounted in a housing 84- on suitable bearings 85. The housing 84 isfixed to the support bracket 76. The shaft 82 is driven with a hydraulicmotor 83 mounted on the bracket 76. The hydraulic motor is splined toshaft 82 and rotates the gripping assembly about its upright axis withrespect to the support bracket 76 280. Stop members 86 and 87 are usedto limit rotation of the gripping as sembly (see FIG. 8).

Referring specifically to FIGS. and 6, it can be seen that the yokemember 81 includes a base plate 89 to which the shaft 82 is attached,and a pair of depending legs 90,90 which are spaced apart. At the lowerend of the legs coaxial shafts 91,91 are rotatably mounted. At the outerends of the shafts 91 there are drivably mounted arms 92,92 each ofwhich is controlled through the use of a hydraulic cylinder 93. Thehydraulic cylinders 93 are mounted at their base ends to the bracket orplate 89 and at their rod ends to the outer ends of the arms 92, withsuitable pins 94. Extension or retraction of the two cylinders 93 (whichoperate in parallel) will cause the arms to be rotated, thereby rotatingthe shafts 91.

A grip member 95 is mounted on shafts 91,91 between the legs 90,90. Thegrip member 95 includes a mounting block 96. The inner ends of theshafts 91 are drivably mounted to this mounting block 96 so that themounting block 96 rotates about the axis of the shafts 91 when theshafts are rotated. The mounting block 96 has a hydraulic motor 100mounted thereon and this motor 100 in turn drives a shaft 101. The shaft101 supports for rotation therewith a grip base 102. The grip base 102extends downwardly, and has a pair of offset arms 103,103 mounted alongthe sides thereof below the legs A bell crank 104 is positioned betweenthe arms 103 and is pivotally mounted to these arms about an axis 105 ona suitable pin. At the lower end of the bell crank a gripping jaw 106 ispivotally mounted as at 106A, to the bell crank 104 on suitablebrackets. In addition, a pair of links 107 (one on each side of theassembly) are pivotally mounted as at 108 to the arms 103 and has at 109to the gripping jaw 106.

The gripping jaw 106 has a pair of gripping pins 112,112 mounted there,and these pins fit into receptacles 113,113 on the grip base 102. Thegripping jaw 106 is controlled for movement toward and away from thegrip base through the use of a hydraulic cylinder 114 mounted as at 115to an outer end of arms 103,103, and positioned between these arms andwhich has a rod end 116 mounted as at 117 to one end of the bell crank104. Thus, by extension or retraction of the cylinder 114, the bellcrank will be moved about its pivot and the gripping jaw 106 will movein and out with respect to the grip base. The links 107 are pivotallymounted in relation to the pivots and 106A so that it acts like aparallel link member so that the gripping jaw 106 moves back and forthand remains parallel to its original position. This means that the pins112 will move in and out with respect to the grip base in a parallelrelation. A bracket 120 is bolted to a section of mill liner 121 whenthe liner is to be removed, and the grip member then can be used forattaching or gripping the bracket, and handling the liner section 121.

The gripping assembly which is a heavy-duty unit, has sufficientmovements to get into the odd corners of the mill and can be positionedat different angles in order to grasp the mill liner sections. It willrotate about an upright axis through the operation of motor 83, and thismoves the yoke supporting the grip member itself. The grip member tiltsabout an axis at right angles to this axis through the use of thehydraulic cylinders 93,93. The grip member also is rotatable about anaxis at right angles to the tilting axis. Thus, by tilting the axis ofrotation of the grip member, with respect to the axis of rotation of thegrip assembly, the position of the gripping jaws can be moved to manydifferent positions in order to grasp the mill liner sections. Theopening of the gripping jaws operates through a hydraulic cylinder whichgives exceedingly large force and good holding force. The fact that thepins for supporting the mill liners enter receptacles in the jaw basealso ensures that adequate strength is achieved for supporting the heavyloads from the mill liners.

Referring specifically to FIGS. 3 and 4, the unique hanger memberassemblies for the machine are shown. The hanger members each comprisebase sections 124 which are attached directly to the crossmembers 20 atopposite ends thereof. (There are four hanger members). The base section124 each have two portions 125A and 1253. As shown in FIG. 3, the twoportions 125A and 125B forming each section 124 are spaced apart. Theportions 125A and 125B have slots 126 defined therein near the upperedges thereof and these slots face each other, as shown, to form aslide, guideway in which roller supports 127 are slidably mounted. Thereare two roller supports 127 supported by each of the base members 125,one roller on each side of the web 15 of the channels. The rollersupports have a' T-shaped lower section 128. The outer edges of the Tsection are made so that they fit within the slots 126 and slide inthese slots. Each of the roller supports 127 mounts a separate guideroller 131 adjacent the upper portions thereof on a shaft 132 that isfixed to the roller support and has bearings thereon which the rollers131 rotate. The movement of the roller supports 127 and consequently therollers 131 along the slots 126 is controlled through the use of ahydraulic cylinder 133. One end of the cylinder is attached as at 134 tobrackets 135 that are attached to the roller support 127 on a first sideof the associated beam 13, and the rod end of the cylinder 133 isattached as at 136 to brackets 137 fixed to the roller support 27,roller support 127 on the opposite side of the beam 13.

The cylinder 133 is positioned between the portions 125A and 1253 ofeach base section 124. By directing fluid under pressure to the cylinder133 the rollers 131 can be either spaced apart to their dotted positionsshown in FIG. 4, or moved together to position shown in solid lineswherein the outer surfaces of the rollers mate with the lower flange 16of the beam 13.

Stop members 141 are provided on opposite ends of the base sections 124.These stop members are bolted into the ends of portions 125A and 125Band close the ends of slot 126. A detentsafety lock member 142 ispositioned at each end of the slots. The safety lock members have ashank portion 143 slidably mounted on the roller supports, and a footmember 144 that will move into and out of interfering relationship withstop member 141. When the rollers are positioned on the beam 13, thesafety stop members are positioned in locked position as shown in FIG. 4in solid lines. The foot member. 144 will abut against stop member 141if the roller support 127 moves outwardly. This will prevent the rollersupport from moving sufficiently far to let the roller release from theflange of the beam. This then prevents the entire machine from comingoff the beam if the cylinders 133 should fail.

When the machine is to be removed from the rails 13 the lock members 142are slid upwardly so the foot member clears the stop member 141. Thisposition is shown in dotted lines in FIG. 4. Then the rollers 131 can bemoved to clear the flange 16 of the beams. The lock members are held inthe lifted position with a spring latch 148 which has a bolt or pin thatfits into a notch or detent on the shank when the shank is lifted. Alarge hole 143A is formed adjacent the top of the shank 143 as seen inFIG. 3, and a pole can be placed in this hole and used to lift' the lockmembers up to released positions or lower them to locked position. Theoperator can stand on the floor to actuate these lock members with thepole.

A pair of bolts 145,145 are used to hold the portions 125A and 1258together. These bolts 145 pass through the space between the rollersupport members of each hanger.

A separate bottom guide roller 146 is mounted onto brackets 147 attachedto each end of each of the crossbeams 20. The rollers position thecarriage assembly properly with respect to the bottom of the web 16. Therollers 131 ride on top of the web 16 of the beams.

The lengths of the inner boom section 40 and the outer boom section 61are selected so that they can substantially equal in length when theouter boom is retracted.

Upon retracting the outer boom section, the grip assembly will besupported thereon close to the base portion 71. Then, when the outerboom section is folded back against the inner boom section, it will beseen that this grip member will be close to the support tube 35. Theentire carriage can be moved out of the mill with cylinder 30 along therails 13 so that this folding can take place. 7

Once the outer boom section is folded back against the inner boom, theinner boom is rotated about the axis of tube 35. The grip assembly,which is relatively heavy, will stay adjacent to the tube 35 and thepivot between the inner boom and the outer boom will be positionedsubstantially below the motor 26 and reservoir 27 for hydraulic fluid.It should be noted that the length of the outer boom when it is rotatedwill approximate that of the rails 21 of the carriage so that forstorage the entire boom will fold to substantially the same length asthe carriage used for supporting it. The heavy grip assembly is on theside of the support 24 opposite from the heavy motor 26 and reservoir27. The positioning of the hydraulic reservoir is intentional to balancethe weight of the grip assembly so that the entire unit can be liftedconveniently at a point within the confines of the carriage.

Thus, the storage of the unit becomes simple, and space is kept to aminimum. The boom folds to a length substantially equaling that of itssupport carriage, and the heavy grip as sembly is balanced by the motorand hydraulic reservoir which are carried right with the unit.

When the carriage unit is to be removed from the rails 13, the unit ispicked up by a support bar 24 with a suitable crane or other mechanismuntil the weight is off the hanger assemblies. The lock members 142 arethen lifted to their release position. The cylinders 133 for each of theroller assemblies are extended by actuating the valves, releasing therollers 131 from the flange 16. Then the unit can be dropped down andplaced in storage, if desired. When the unit is to be replaced, it ismerely lifted upwardly until the rollers 146 contact the cross bars 120,and then the cylinder 133 (which has been extended to move the rollersupports to their dotted position shown in FIG. 4) are retracted,pulling the rollers up onto the bottom flan'ge of the rail 13. The lockmembers 142 are then placed in locked position. It will be noted thatthe rollers 131 have part conical outer surfaces mating with the uppersurface of the flanges 16 ofthe ordinary I beams. This will tend to pullthe carriages up into a tight position so that they are firmly supportedon the rails. After that, the unit is ready to use, and the inner boomcan be rotated about its pivot from its folded condition, the outer boomassembly unfolded, and the carriage rolled along the rails 13 to put theboom into the interior of the mill. By proper manipulation the linersections, even in the remote corners of the mill, can be lifted out forreplacement.

All of the hydraulic cylinders and components, with the exception of thecylinders 133 used for controlling the position of roller 131 on thesupport rail 13 utilize remote controls. The flow of hydraulic fluidfrom the pump shown schematically at 28 in FIG. 2 is controlled throughindividual solenoid valves which are shown in a group schematically at29. Individual solenoid valves are shown schematically for theindividual components and these are labeled SV in the drawings. Aportable controller 33 comprises a handheld control box that haselectrical switches for controlling the solenoid valves. The switchesare shown in the copending U.S. Pat. application of Karl E. Neumeier,Ser. No. 725,617, filed May 1, 1968. In FIG. 50f U.S. Pat. applicationSer. No. 725,617, the typical circuit utilized with the present deviceis shown. The solenoid coil 41 in U.S. Pat. application Ser. No. 725,617would control individual solenoid valves of. the present device, andthere is one separate finger switch for each of the different movementsor motions. This would include the rotary motions utilizing hydraulicmotors, as well as cylinders 30, 44, 63, 72, 93 (which operate inparallel) and 114.

A manual valve 34 is used for closing off flow of fluid under pressuretothe solenoid valves when the unit is first installed, and this stillpermits fluid to flow from the pump 28 to a control valve used foroperating the cylinders 133 in opposite directions. The unit isself-contained and the motor has to be only connected to power to obtainhydraulic pressure. The valve 130 is manually controlled so that it ispositive acting, and it is connected in separately so that the solenoidvalves are deactivated and valve 130 will still work. Then, there willnot be any accidental movement of the various components controlled bythe solenoid valves before the unit is properly installed on rail 13.

Once the cylinders 133 have been properly positioned so that the rollers131 are securely in place on the rails 13, and the roller lock membersare in place as well, the manual valve 34 is opened, and then thesolenoid valves can be controlled through the individual switches in theportable controller 33. Theseindividual switches are indicated by theletter S schematically in several of the drawings.

Referring specifically to FIGS. 10 and 11, a modifiedcarriage-propelling mechanism is shown. The rails 13,13 are shownsupported on walls 149 and 150 respectively. The wall 150 of coursewould be a support or wall adjacent the mill, and the carriage 17 ismounted as before on the rails 13,13 for movement back and forth indirections along the rails. The details of the carriage and thesupporting mechanism is exactly the same, but in this instance, a winchassembly or member 151 is mounted onto the top of the rear crossmember20. The winch assembly has a support member 152 that is fixed to thiscrossmember 20 and the support member 152 rotatably mounts adouble-sided winch drum 153. The winch drum has a center shaft 154 thatis driven with a conventional worm gear set illustrated at 155. The wormof the worm gear set 155 is rotatably driven through the use of ahydraulic motor 156 that obtains power from the source or pump 28 andthat is controlled through a suitable control valve.

A first side of the winch drum 153 has a cable length 157 mountedthereon, and the end of cable length 157 is fastened as at 158 to thewall150. The second side of the winch drum 153 has a cable length 161mounted thereon and the end of thiscable length in turn is fastened asat 162 to the wall 149. The cable lengths are wound on the drum inopposite directions (one clockwise and one counterclockwise).

The cable lengths are adjusted at their fastening means so that they aretaut when the unit is in place on the rails 13, and by powering themotor 156 in a first direction, the cable lengths 157 will be wound uponto the drum 153 and the carriage 17will move in direction as indicatedby the arrow 163.

The length 161 will feed out as the carriage moves. When the motor 156is rotated in the opposite direction by operation of its control valve,the cable length 161 will be wound onto the drum 153 and the cablelength 157 will be paid out, so that the carriage will move in oppositedirection from that indicated by arrow 163. The use of the cable lengthspermits fastening the propulsion means for the carriage at remotepoints, and the cable length can be any desired length, and can extendout beyond the limits of the support rails 13 if desired. The rest ofthe unit will operate exactly the same, but the cylinder 30 is nowreplaced with the winch assembly.

In FIGS. 12 and 13 a replacement for the gripping assembly 80 is shown.In this instance, the motor 83 drives the shaft 82 that is rotatablymounted on the housing 84, as before, but the outer end of the shaft 82has a stub beam 167 drivably mounted thereon. The beam, as shown, merelyextends at right angles to the shaft and has a wide base portion 168 anda narrow fastening portion 169 which in turn has an opening 170 therein.The beam will rotate in both directions of rotation about an uprightaxis as indicated by the arrow 1'71, and by using the opening 170, achain or hook can be extended down to a fastening bracket on the millliners, and the unit can be used for lifting the sections withoutoperating the gripping mechanism. A stub beam 167 does result in someadditional effort, because the positioning can be more exact with thegripping device. However, the stub beam can get into many corners andoperate satisfactorily in most situations. The support beam assembliesare all the same as before, and can be extended, retracted and pivotedas explained previously. The stub beam forms a means for lifting andsupporting the mill liners on the outer beam.

By using the portable controller, an operator can carry the controllerwith him up to the gripping end of the boom where the liners are to behandled, and can control the positioning of the boom, and the operationof the grip, while he stands right next to it to see where the grip isbeing placed. The controller can be carried by the operator with ashoulder strap or harness so both hands are free to operate thecontrols.

The liner sections weigh up to 2,000 pounds, and because of the largesize of the mill, it can be seen that there are tremendous forces placedon the boom at its mounting. However, the rugged construction, and thereliable positioning through the hydraulic control members permits theboom to be moved even out to the lateral sections of the mill, or inother words quite far laterally offset from its mounting member, withoutdamage.

lclaim:

1. An articulated boom assembly having lifting means for operatinginside a structure having a relatively narrow opening, and greaterlateral width than said opening and in which the lifting means have towork, including support means exterior of said structure adjacent saidopening, carriage means movably mounted on said support means formovement in direction toward and away from said opening, means to attachsaid carriage means to said support means, a first boom section, meansto pivotally mount said first boom section about a first pivot axis tosaid carriage means, a second boom section, means to pivotally mountsaid second boom section to the outer end of said first boom sectionabout two mutually perpendicular axes, one of which is parallel to thefirst pivot axis, said first boom section being offset adjacent itsouter end so that one pivot axis of said second boom section is offsetlaterally of a plane defined by the longitudinal axis of said first boomsection sufficiently so that said second boom section will fold backtoward said first boom section about its one pivot axis to a positionsubstantially parallel to and in alignment with said first boom section.

2. The combination as specified in claim 1 wherein said.

second boom section comprises an inner member and an outer member, andwherein said outer member is slidably mounted within said inner memberfor longitudinal axial movement, and power means to move said outermember axially with respect to said inner member.

3. The combination as specified in claim 1 wherein said support meanscomprise rail members having a central web extending substantiallyupright, and flanges extending substantially horizontal and on oppositesides of said rail members, said carriage means having pairs of rollersrotatably mounted thereon and adapted to roll along the flanges of saidrail members on opposite sides of the web, separate roller carrier meansfor carrying each of said rollers of each pair, hydraulic cylinder meansconnected between said separate roller carrier means for each pair ofsaid rollers, said hydraulic cylinder means being'mounted to saidseparate roller carrier means for each pair so that upon extension orretraction of each of said hydraulic cylinder means, said roller carriermeans of the associated pair will move toward and away from said web.

4. The combination as specified in claim 3 and safety mechanical stopmeans for preventing said roller carrier means from moving past positionwhere they engage the flanges of said support means.

5. An articulated boom assembly having lifting means for operatinginside a structure having a relatively narrow opening, and greaterlateral width than said opening, and in which the lifting means have towork, including support means exterior of said structure adjacent saidopening, carriage means movably mounted on said support means formovement in direction toward and away from said opening, means to attachsaid carriage means to said support means, a first boom section, meansto pivotally mount said first boom section about a first pivot axis tosaid carriage means, a second boom section, means to pivotally mountsaid second boom section to the outer end of said first boom sectionabout two mutually perpendicular axes, one of which is parallel to thefirst pivot axis, said first boom section being offset adjacent itsouter end so that one pivot axis between said first boom section andsaid second boom section is offset to the side of the longitudinal axisof said first boom section to permit folding said second boom sectionback toward said first boom section, said lifting means comprisinggripping means, an outer end ofsaid second boom section supporting saidgripping means, said gripping means comprising a grip assembly, means torotatably support said grip assembly adjacent the outer end of saidsecond boom section about a first grip axis, means to rotatably drivesaid grip assembly about the first grip axis, an openable and closablegrip member, means to rotatably mount said grip member to said gripassembly about a second grip axis substantially perpendicular to saidfirst grip axis, power means to control movement of said grip memberaround its second grip axis, means to rotatably mount said grip memberabout a third grip axis at substantially right angles to said secondgrip axis, and for movement independently of movement of said gripassembly about the first grip axis, power means to rotate said gripmember about its third grip axis, and power means to open and close saidgrip member to provide for grasping of objects to be moved.

6. The combination as specified in claim 5 wherein said grip membercomprises a main mounting block, a movable member movable toward andaway from said main mounting block, said main mounting block havingreceptacles thereon, pin members on said movable member and adapted tofit within saidreceptacles on said mounting block, said pin membersbeing of length so they will enter said receptacles while supporting aload.

7. The combination as specified in claim 6 wherein said movable memberhas parallel link members connecting it to the grip member, said movablemember moving in a parallel relationship with respect to said mountingblock from a full opened to a closed position.

8. The combination as specified in claim 7 wherein one of said linkmembers for mounting said movable member comprises bell crank means,said bell crank means being pivotally mounted with respect to said gripmember about a first pivot and pivotally mounted to said mounting blockabout a second pivot, a hydraulic cylinder mounted to said bell crankmember at a point spaced from a line drawn through the first and secondpivots, and means to control movement of said hydraulic cylinder therebyto move said bell crank aboutits second pivot and move said movablemember toward and away from said mounting block.

9. The combination as specified in claim 2 wherein said outer member hasguide ribs on the top and bottom thereof and roller means which engagesaid outer section on opposite sides of said guide ribs.

10. An articulated boom assembly having lifting means for operatinginside a structure having a relatively narrow opening, and greaterlateral width than said opening and in which the lifting means have towork, including support means exterior of said structure adjacent saidopening, carriage means movably mounted on said support means formovement in direction toward and away from said opening, means to attachsaid carriage means to said support means, a first boom section, meansto pivotally mount said first boom section about a substantiallyhorizontal pivot axis to said carriage means, a second boom section,means to pivotally mount said second boom section to the outer end ofsaid first boom section about a substantially upright axis, said firstboom section being offset adjacent its outer end so that the axisbetween said first boom section and said second boom section is offsetto the side of a plane defined by the longitudinal axis of said firstboom section and a line perpendicular to the pivot axis of said firstboom section to permit the second boom section to be folded backparallel to and adjacent the first boom section, said first and secondboom sections being substantially the same length when folded, means torotatably mount the first boom section about an upright axis adjacentone end of the carriage means, said first and second boom sections infolded condition being rotatable about the upright axis of rotation ofthe first boom section to position aligned with said carriage means.

11. The combination as specified in claim 10 wherein movement of saidboom sections is controlled by hydraulic power means including a pumpand fluid reservoir, means to mount said pump and'fluid reservoir onsaid carriage means in position so the center of gravity of saidcarriage means and boom assembly is within the confines of said carriagemeans.

12. The combination as specified in claim 11 and a hydraulic cylinder,means to connect the last-mentioned hydraulic cylinder to said carriageand to a fixed support, and hydraulic power means to extend and retractthe last-mentioned hydraulic cylinder to cause said carriage to movealong said support means.

13. The combination as specified in claim 12 and a winch member mountedon said carriage, said winch member having a rotatable drum and twolengths of cable wound thereon in opposite directions, said cablelengths extending in opposite directions and being fastened to fixedsupports independent of said carriage, said lengths of cable beingoperatively connected to said drum so that as said drum rotates one ofsaid lengths is shortened and the other of said lengths is lengthened,and means to selectively rotate said drum in opposite direction to causesaid carriage to move with respect to said fixed supports.

14. An articulated boom assembly having lifting means for operatinginside a structure having a relatively narrow open ing, and greaterlateral width than said opening and in which the lifting means have towork, including support means exterior of said structure adjacent saidopening, carriage means movably mounted on said support means formovement in direction toward and away from said opening, means to attachsaid carriage means to said support means, a first boom section, meansto pivotally mount said first boom section about a first pivot axis tosaid carriage means, a second boom section, means to pivotally mountsaid second boom section to the outer end of said first boom sectionabout a second axis which is perpendicular to the first pivot axis, saidfirst boom section being offset adjacent its outer end so that thesecond axis is offset to the side of a plane defined by the longitudinalaxis of said first boom section and a line perpendicular to the firstpivot axis of said first boom section, said lifting means comprising ashort lift beam, means to rotatably mount said short lift beam to theouter end of said outer beam section adjacent one end of the short liftbeam, and about an upright axis, and power means to rotate said shortbeam about its upright axis.

